The sister of Craig Lehner, the Buffalo police officer who died during a dive training accident in the Niagara River in October, says the Buffalo Police Department should not have allowed the training exercise to take place because it was too dangerous, that her brother had not been properly trained before going into the water and that his diving equipment was "in dangerous, unsafe and/or defective condition," according to court papers she filed late last month.

Lehner, a K-9 officer who joined the Buffalo Police Underwater Recovery Team six months before his death, had just jumped into the water for a training exercise in the fast-moving waters of the Niagara River when he ran into trouble. A frantic recovery effort followed as law enforcement officers and first responders from around the region came to assist. On the fifth day of searching, Lehner's body was recovered about two miles downstream.

Lehner's sister, Donna Wilson, filed a notice of claim, the first step in a lawsuit, against the City of Buffalo and the Buffalo Police Department on Jan. 25. In it, she says the training accident "was caused by the reason of negligence, recklessness and carelessness" of the city and police department.

The notice of claim alleges that:

* The training exercise was allowed to take place "despite reasonably dangerous conditions."

* Lehner, 34, was not sufficiently trained or supervised when he went into the water.

* The diving equipment was in "dangerous, unsafe, and/or defective condition," wasn't properly inspected and was "inefficient to provide reasonable and adequate" protection for Lehner, creating the conditions that led to the equipment to fail and prevented Lehner's rescue.

* The city and police department violated state labors laws in "failing to furnish its employees with a place of employment free from recognized hazard that caused or were likely to have caused death or serious physical harm to its employees."

"The Buffalo Police Department trains in those waters to be ready to respond if needed," said Buffalo Police Capt. Jeff Rinaldo.

Lehner's fatal dive was the police department's first training exercise in the Niagara River in 2017 and Lehner's first training in the Niagara.

The state Labor Department is conducting an investigation into Lehner's death. The Buffalo Police Department conducted its own investigation into the death and has not released the report. Police officials said Wednesday they want to review the Labor Department's findings before releasing their internal report.

Police sources said Wednesday the internal investigation found that Lehner's tether got snagged on a boulder at the bottom of the river, which spun him around in the water, causing the current to knock the regulator out of his mouth. They also said there were no indications of equipment failure.

After Lehner's death, the Buffalo's Underwater Recovery Team suspended training exercises in the Niagara River for the rest of the year.

Lehner was a nine-year veteran of the Buffalo Police Department and joined the Underwater Recovery Team in April 2017.

Before joining the team, prospective members need to be certified scuba divers. Once accepted, members train for a year before becoming a permanent member. Lehner was still going through the year of training.

The commander of the department's dive team, Leo McGrath, is not certified as a master diver or as a scuba instructor, police confirmed. But officials said that is not required.

When Lehner jumped Oct. 13 into the swift moving waters off Bird Island Pier, he was in water that was about 25 or 30 feet deep. A fellow member of the police Underwater Recovery Team was holding the tender line, which is standard practice for dives of this nature, police sources told The Buffalo News in October.

Lehner was in the water for less than five minutes when the team member holding the tether line noticed it suddenly tightened. The line then went slack, and then tightened again, police sources said.

His team members feared he was trapped, possibly tangled in old fishing lines or debris. A rescue effort followed, starting at about 12:50 p.m. Oct. 13. Two divers tried to follow the tender line down to Lehner but the current was too strong and they could not locate him, police sources described to The News.

Team members next threaded an emergency air tank to the tender line and attempted to send it down to Lehner, but again the current proved too strong and the tank would not sink to the river bottom. It was later found floating near the pier.

The Buffalo police divers called for assistance, and the U.S. Coast Guard dispatched a 45-foot response boat that arrived at approximately 1:10 p.m., according to the Coast Guard.

With the tender cable extended to its full length, 300 feet, and attached to the boat, the Coast Guard crew pulled from different directions, hoping to unsnag the line. A police diver went down on the line from the boat. But the line snapped, police sources said.

When Lehner's body was found floating in the river a few thousand feet north of the International Railway Bridge on Oct. 17, he was still wearing much of his gear, his air tank, a regulator, a buoyancy compensator and a 40-pound weight belt, according to police. His face mask was missing. He had with him two knives and a pair of surgical scissors.

Several inches of a tender line were still connected to a harness ring on Lehner's suit. The end of the line was frayed, and did not appear to have been cleanly cut, which likely means it tore or snapped and wasn't cut, police and diving experts consulted by The Buffalo News in October said.

Divers are trained to ditch their weights and inflate the buoyancy compensator, a vest designed to fill up with air, if they need to get to the surface, diving experts said in October.

Lehner's tank was found more than half-full of air, about 1,600 psi (pounds per square inch), police said. The diving experts said that would provide as much as about an hour of air, depending on the diver's exertion levels.

An autopsy showed he had drowned and he had water in his lungs, police said. There was also a gash on his forehead and trauma to his head.

On WGRZ-TV, Channel 2, Daniela Porat of Investigative Post reported Wednesday evening Lehner had taken training dives five times in the still waters of the Buffalo River and Union Ship Canal. She added he had gotten his scuba certification in the Caribbean in 2014 in still waters.

Porat reported Lehner was not wearing a quick release device to disconnect from his tether. She noted the Buffalo Police Department does not use them and divers are trained to cut the rope on their connection. She said Lehner was not wearing a face mask that would allow him to communicate electronically with officers on the surface.